This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. The subproject and investigator (PI) may have received primary funding from another NIH source, and thus could be represented in other CRISP entries. The institution listed is for the Center, which is not necessarily the institution for the investigator. Decoy Receptor 3 (DcR3) is a secreted immunosuppressive protein that belongs to the Tumor Necrosis Factor (TNF) receptor superfamily. The dissection of DcR3's functional mechanism is complicated by its capacity to neutralize three different TNF ligands: FasL, LIGHT, and TL1A. Each of these ligands binds distinct functional receptors and subsequently directs immune responses to different destinations. The understanding of the interactions between DcR3 and its ligands may provide therapeutic opportunities to a variety of human diseases, including Chron's disease and rheumatoid arthritis.